(1) Field of the Invention
The present invention generally relates to a tape loading mechanism, and more particularly to a tape loading mechanism for use in a digital audio tape recorder, which realizes a reduction of the total height thereof by using a simple structure.
(2) Description of the Prior Art
FIGS. 1 and 2 show a conventional tape loading mechanism 10 for use in a rotary head type digital audio tape recorder (R-DAT). The tape loading mechanism 10 includes a main chassis 11, a sub-chassis 12, a rotating drum 13, and a loading post assembly 14.
The loading post assembly 14 includes a base 15, a supporting member 16, a loading post 17, a slanting post 17a, a guide pin 18, a retaining plate 19, and a screw 20. The supporting member 16 is secured to the base 15 and passed through it. The supporting member 16 includes a guide pin portion 16a downwardly projecting from the base 15 and a contact portion 16b upwardly projecting toward the loading post 17.
The loading post 17 is arranged on the supporting member 16. The guide pin 18 is attached to the base 15 by fitting the screw 20 into the base 15. The retaining plate 19 is staked to the guide pin 18 so as to prevent the lifting of the loading post assembly 14 from the sub-chassis 12.
The guide pin portion 16a and the guide pin 18 are fitted onto a guide groove 12a of the sub-chassis 12. Thus, the loading post assembly 14 is slidable on the sub-chassis 12 along the line of the guide groove 12a.
A first loading arm 21 has one end connected to the bottom end of the guide pin 18. A second loading arm 22 has one end rotatably supported by a pin 23 of the main chassis 11. A connecting pin 24 is staked to the other end of the first loading arm 21. The first loading arm 21 and the second loading arm 22 are linked to each other by the connecting pin 24.
A drum base 25 is threaded on the sub-chassis 12. The drum base 25 has a stopper portion 25a which is cut into a V shape.
As shown in FIG. 2, when the second loading arm 22 is rotated by a drive unit (not shown) in a direction indicated by the arrow A, the loading post assembly 14 is pushed by the first loading arm 21 so that the loading post assembly 14 is moved along the guide groove 12 in a direction indicated by the arrow B.
When the contact portion 16b comes into contact with the stopper portion 25a of the drum base 25 due to the movement of the loading post assembly 14, the loading post assembly 14 is in its loading end position.
A tape cassette (not shown) is inserted in the digital audio tape recorder, and a magnetic tape 30 is taken out from the tape cassette by the loading post 17. The magnetic tape 30 from the tape cassette is loaded by the loading post 17 onto a tape path on the rotating drum 13.
In the tape loading mechanism 10 described above, the stopper portion 25a has to be inserted between the base 15 and the loading post 17. Thus, it is necessary to allow for a certain distance from the base 15 to the loading post 17 within the tape loading mechanism 10. Accordingly, the distance from the base 15 to the loading post 17, indicated by "a" in FIG. 1, is relatively great, which increases the height of the loading post assembly 14 within the tape loading mechanism 10 to a height indicated by "d" in FIG. 1.
In the tape loading mechanism 10 described above, the retaining plate 19 and the first loading arm 21 overlap, and the first loading arm 21 and the second loading arm 22 further overlap. Thus, it is necessary to allow for a relatively great distance between the main chassis 11 and the sub-chassis 12, which is greater than the sum of thicknesses of the retaining plate 19, the first loading arm 21 and the second loading arm 22. Accordingly, the distance between the main chassis 11 and the sub-chassis 12, indicated by "b" in FIG. 1, is relatively great.
For the reasons described above, the distance from the main chassis 11 to a center line 31 of the magnetic tape 30 of the loading post 17, indicated by "h1" in FIG. 1, is relatively great, which increases the total height of the tape loading mechanism 10 to a height indicated by "h2" in FIG. 1. As the conventional tape loading mechanism has to allow for relatively great dimensions as described above, it is difficult to realize a reduction of the total height of the tape loading mechanism.